172 Master Mi?ids of Modern Science 



All through the nineteenth century inventors experi- 

 mented with the turbine, but none of them got far with it. 

 All could drive wheels with steam jets, but the waste of 

 steam was so great that the work done by the steam could 

 not compare with that done by the reciprocating engine. 

 The turbine got a bad name as a ' steam-eater/ and the 

 general opinion among engineers was that it would never 

 be of any practical value. One of the few men who held 

 the opposite opinion was the great Lord Kelvin. 



But Charles Parsons was something more than an 

 inventor ; he was a scientist and understood the laws of 

 thermo-dynamics (power produced by heat) . He realized 

 the possibilities of the turbine and set himself patiently to 

 work to overcome its difficulties and disadvantages. 



The reciprocating engine is one in which steam-pressure 

 propels a piston connected with a crank by means of 

 which the to-and-fro movements are converted into rotary 

 action. In the turbine this action is obtained by making 

 steam drive direct upon vanes or blades attached to the 

 rotary parts, so that the steam does its work in a much 

 more simple and direct manner. The chief contrast 

 between the two forms of engine is that in the recipro- 

 cating engine the steam has a velocity of less than one 

 hundred feet per second, while in the turbine it attains 

 the tremendous velocity of two thousand to three thousand 

 feet a second. 



There are several reasons why the reciprocating engine 

 can never make use of anything like the full power of 

 steam. One is the alternate heating and cooling of the 

 cylinder walls; another is the friction due to the large 

 number of rubbing surfaces ; a third is that momentum 

 and inertia must be overcome at every stroke of the 

 piston ; and a fourth the fact that if superheated steam is 

 used the oil for internal lubrication carbonizes. 



The advantages of the turbine are that the motion is 

 continuous, there is no vibration, no need for internal 



